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POST UTME GREENFIELD UNIVERSITY 2021 Chemistry | Objective

Are you preparing for POST UTME GREENFIELD UNIVERSITY exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2021 Chemistry (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1

Determine the number of moles of electrons transferred during the electrolysis of 2.5 L of 0.5 M H2SO4.

Correct A. 1.25 mol

B. 2.5 mol

C. 5.0 mol

D. 6.25 mol

Correct Answer: A

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Question 2

A sample of polystyrene contains 25% by mass of styrene monomer. If 50 g of the sample is burned, what is the mass of styrene monomer combusted?

Correct A. 6.25 g

B. 12.5 g

C. 25.0 g

D. 50.0 g

Correct Answer: A

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Question 3

The half-life of 14C is 5730 years. If a sample contains 50% of the original amount of 14C, how many years have passed?

A. 1000 years

B. 2000 years

Correct C. 5730 years

D. 11460 years

Correct Answer: C

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Question 4

A solution contains 0.1 M CuSO4. If 25 mL of this solution is diluted to 100 mL, what is the new concentration?

A. 0.01 M

Correct B. 0.05 M

C. 0.1 M

D. 0.2 M

Correct Answer: B

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Question 5

A diagram of a redox reaction is shown below. What is the oxidation state of the underlined atom?

Correct A. +2

B. -2

C. +1

D. -1

Correct Answer: A

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Question 6

Determine the oxidation state of the underlined atom in the compound [Cr\( H_2O \)_5Cl]Cl_2.

A. +3

B. +2

C. +1

Correct D. +6

Correct Answer: D

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Question 7

A 25.0 mL sample of 0.150 M HCl is mixed with 50.0 mL of 0.100 M NaOH. Calculate the number of moles of HCl that react with NaOH.

Correct A. 0.00375

B. 0.00425

C. 0.00475

D. 0.00525

Correct Answer: A

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Question 8

The diagram below shows a setup for the electrolysis of water. What is the purpose of the U-tube?

A. To measure the volume of the electrolyte

Correct B. To collect the hydrogen gas

C. To prevent the electrolyte from overflowing

D. To measure the temperature of the electrolyte

Correct Answer: B

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Question 9

A solution contains 0.0500 M KNO_3. What is the concentration of K^+ ions in the solution?

Correct A. 0.0500 M

B. 0.100 M

C. 0.150 M

D. 0.200 M

Correct Answer: A

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Question 10

The diagram below shows a setup for the titration of a strong acid with a strong base. What is the purpose of the burette?

A. To measure the volume of the acid

Correct B. To measure the volume of the base

C. To prevent the acid from overflowing

D. To measure the temperature of the acid

Correct Answer: B

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Question 11

Determine the rate cons\tant (k) for the reaction: A → B + C, given that the initial concentration of A is 0.5 M, and after 20 minutes, the concentration of A has decreased to 0.2 M. The rate cons\tant is related to the half-life \( t1/2 \) by the equation: k = ln(2) / t1/2.

Correct A. 0.05 min^-1

B. 0.1 min^-1

C. 0.2 min^-1

D. 0.5 min^-1

Correct Answer: A

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Question 12

A polymer has a molecular weight of 100,000 g/mol and a degree of polymerization (DP) of 500. Calculate the molar mass of the repeating unit of the polymer.

A. 200 g/mol

Correct B. 500 g/mol

C. 1000 g/mol

D. 2000 g/mol

Correct Answer: B

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Question 13

A solution contains 0.1 M NaCl. If 10 mL of this solution is diluted to 100 mL, what is the concentration of Na+ ions in the final solution?

Correct A. 0.01 M

B. 0.05 M

C. 0.1 M

D. 0.2 M

Correct Answer: A

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Question 14

A sample of a gas occupies a volume of 2.5 L at a pressure of 1.5 atm. If the temperature is increased to 300 K, what is the new volume of the gas?

A. 3.5 L

Correct B. 4.5 L

C. 5.5 L

D. 6.5 L

Correct Answer: B

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Question 15

A solution contains 0.05 M HCl. If 20 mL of this solution is added to 100 mL of 0.1 M NaOH, what is the concentration of the excess reac\tant?

A. 0.01 M

B. 0.05 M

Correct C. 0.1 M

D. 0.2 M

Correct Answer: C

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Question 16

Determine the pH of a 0.1 M solution of HCl in water at 25°C, given that the dissociation cons\tant of HCl is 10^\( -7 \).

A. 1

B. 2

C. 3

Correct D. 4

Correct Answer: D

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Question 17

A 2.5 g sample of a hydrocarbon is burned in a bomb calorimeter, relea\sing 12.5 kJ of heat. Calculate the molar mass of the hydrocarbon.

A. 12

B. 24

Correct C. 36

D. 48

Correct Answer: C

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Question 18

A solution of NaOH is prepared by dissolving 4.0 g of NaOH in 100 mL of water. Calculate the molarity of the solution.

A. 0.1

B. 0.5

Correct C. 1.0

D. 2.0

Correct Answer: C

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Question 19

A 25 mL sample of a 0.1 M solution of HCl is titrated with a 0.1 M solution of NaOH. Calculate the volume of NaOH required to reach the equivalence point.

A. 25 mL

B. 50 mL

C. 75 mL

Correct D. 100 mL

Correct Answer: D

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Question 20

A 2.0 g sample of a polymer is dissolved in 100 mL of water. Calculate the concentration of the solution in g/L.

A. 20 g/L

B. 40 g/L

Correct C. 60 g/L

D. 80 g/L

Correct Answer: C

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Question 21

Determine the pH of a 0.1 M solution of HCl at 25°C.

Correct A. 1

B. 2

C. 3

D. 4

Correct Answer: A

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Question 22

A 25 mL sample of a 0.5 M solution of NaOH is titrated with 0.1 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.

A. 0.0125

Correct B. 0.025

C. 0.0375

D. 0.05

Correct Answer: B

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Question 23

The diagram below shows a titration setup. Identify the part labeled A.

Correct A. Burette

B. Beaker

C. Conical Flask

D. Test Tube

Correct Answer: A

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Question 24

A 0.1 M solution of H2SO4 is titrated with 0.1 M NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.

A. 1

Correct B. 2

C. 3

D. 4

Correct Answer: B

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Question 25

The diagram below shows a chemical apparatus setup. Identify the part labeled B.

A. Beaker

Correct B. Burette

C. Conical Flask

D. Test Tube

Correct Answer: B

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